Improved voltage sweep.

include/Positions.h

@@ -19,7 +19,7 @@ struct FrequencyRange
 const Filter FG_71MHZ = {71000000U, LOW, LOW};
 const Filter FG_120MHZ = {120000000U, LOW, HIGH};
 const Filter FG_180MHZ = {180000000U, HIGH, LOW};
-const Filter FG_260MHZ = {260000000U, HIGH, LOW};
+const Filter FG_260MHZ = {260000000U, HIGH, HIGH};
 
 // All fitlers
 const Filter FILTERS[] = {FG_71MHZ, FG_120MHZ, FG_180MHZ, FG_260MHZ};

src/ATM.ino

@@ -108,7 +108,7 @@ void setup()
   adf4351.begin();
 
   adf4351.setrf(25000000U);
-  adf4351.pwrlevel = 2; // This equals -4dBm*/ For the electrical probe coils one should use at least -20dbm so an attenuator is necessary
+  adf4351.pwrlevel = 2; // This equals 2dBm*/ For the electrical probe coils one should use at least -20dbm so an attenuator is necessary
   adf4351.setf(START_FREQUENCY);
 
   // Setup for the RF Switch for the filterbank

src/commands/VoltageSweep.cpp

@@ -3,9 +3,8 @@
 
 void VoltageSweep::execute(String input_line)
 {
-    int AVERAGES = 4;
-    float VOLTAGE_STEP = 0.1;
     float MAX_VOLTAGE = 5.0;
+    float MIN_VOLTAGE = 0.0;
 
     // First we get the frequency where the voltage sweep should be performed
     float frequency_MHz = input_line.substring(1).toFloat();
@@ -16,19 +15,40 @@ void VoltageSweep::execute(String input_line)
         return;
     }
 
-    // First set the frequency
+    // First set the frequency 2 MHz below the target frequency
+    uint32_t distance = 2000000;
+    setFrequency(frequency - distance);
+
+    // Then we perform a rough voltage sweep with a step size of 1V
+    sweepVoltages(1, MIN_VOLTAGE, MAX_VOLTAGE, MIN_VOLTAGE, MAX_VOLTAGE);
+
+    // Now we set the target frequency
     setFrequency(frequency);
 
-    // Now we can perform the voltage sweep
+    // Then we perform a more precise voltage sweep with a step size of 0.1V but only in the region of the found voltages
-    printInfo("Started voltage sweep");
+    float_t tuning_range = 0.5;
+    sweepVoltages(0.05, tuning_voltage - tuning_range, tuning_voltage + tuning_range, MIN_VOLTAGE, MAX_VOLTAGE);
 
+    // Then we perform a last very precise voltage sweep with a step size of 0.01V but only in the region of the found voltages
+    tuning_range = 0.1;
+    float_t matching_range = 0.2;
+    sweepVoltages(0.01, tuning_voltage - tuning_range, tuning_voltage + tuning_range, matching_voltage - matching_range, matching_voltage + matching_range);
+
+    // Finally we set the found voltages
+    adac.write_DAC(VM, matching_voltage);
+    adac.write_DAC(VT, tuning_voltage);
+}
+
+void VoltageSweep::sweepVoltages(float_t voltage_step, float_t tuning_start, float_t tuning_stop, float_t matching_start, float_t matching_stop)
+{
+    int AVERAGES = 4;
     // We want to maximize the reflection value, so we start with zero
     float_t minimum_reflection = 0.0;
 
     // This bruteforces the optimum voltage for tuning and matching.
-    for (float_t c_tuning_voltage = 0.0; c_tuning_voltage <= MAX_VOLTAGE; c_tuning_voltage += VOLTAGE_STEP)
+    for (float_t c_tuning_voltage = tuning_start; c_tuning_voltage <= tuning_stop; c_tuning_voltage += voltage_step)
     {
-        for (float_t c_matching_voltage = 0.0; c_matching_voltage <= MAX_VOLTAGE; c_matching_voltage += VOLTAGE_STEP)
+        for (float_t c_matching_voltage = matching_start; c_matching_voltage <= matching_stop; c_matching_voltage += voltage_step)
         {
             // Set the tuning and matching voltage
             adac.write_DAC(VM, c_matching_voltage);
@@ -44,9 +64,9 @@ void VoltageSweep::execute(String input_line)
                 tuning_voltage = c_tuning_voltage;
                 matching_voltage = c_matching_voltage;
                 // If the returnloss is better than 14dB, we can stop the voltage sweep
-                float_t reflection_db = (reflection - 900) / 30.0;
+                // float_t reflection_db = (reflection - 900) / 30.0;
-                if (reflection_db > 14)
+                // if (reflection_db > 14)
-                    return;
+                //    return;
             }
         }
     }

src/commands/VoltageSweep.h

@@ -14,6 +14,7 @@ public:
     void printHelp() override;
 
 private:
+    void sweepVoltages(float_t voltage_step, float_t tuning_start, float_t tuning_stop, float_t matching_start, float_t matching_stop);
     float_t matching_voltage;
     float_t tuning_voltage;
 };